Initial Investigation into Helical Milling of Laminated Stacks of Electrical Steel

This paper serves to report the findings of an initial study on the holing of laminated stacks of electrical steels. Three different holing methods were considered: plunge milling, helical milling (orbit milling), and drilling. Stack delamination, axial thrust force, and burr formation were measured at various feed rates for each process and utilized as comparison metrics. Results from the initial experimental investigation indicate that drilling produces significant burr and plunge milling, whilst reducing burr formation compared to drilling, led to delamination of the stack. Helical milling minimized thrust forces, avoided delamination and minimized burr formation. An interesting spring back effect was also observed during the cutting of the laminated stacks. It is concluded that helical milling is a viable and effective processing method for making holes in laminated stack of hard electrical steels.